Aging of Atmospheric Brown Carbon Aerosol
Bibliographic record
Abstract
Emitted by numerous primary sources and formed by secondary sources, atmospheric brown carbon (BrC) aerosol is chemically complex. As BrC aerosol ages in the atmosphere via a variety of chemical and physical processes, its chemical composition and optical properties change significantly, altering its impacts on climate. Research in the past decade has considerably expanded our understanding of BrC reactions in both the gas and condensed phases. We review these recent advances in BrC aging chemistry with a focus on gas phase reactions leading to BrC formation, aqueous and in-cloud processes, and aerosol particle reactions. Connections are made between single component BrC proxies and more complex chemical mixtures as well as between laboratory and field measurements of BrC chemistry. General conclusions are that chemical change can darken the BrC aerosol particles over short time scales of hours close to the source and that considerable photobleaching and oxidative whitening will occur when BrC is a day or more removed from its source.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".